French language Q&A Forum

Bonjour Madame Aurélie,

While doing a test named “Conte de fées” I landed up at a mysterious sentence -

Le père était àgé et sortirait rarement de son lit, alors sa fille devait s’occuper du jardin et des animaux.

Here I would like to ask you why a dû was marked incorrect although the English translation specifies ‘so his daughter had to take care of the garden .....’ . I read your lesson which states that one uses Passé Composé for an obligation that was very well met. And here too is the same case.

The link to the test -

https://progress.lawlessfrench.com/my-languages/french/tests/take/2581800

Please help me to figure out the correct option as I am not very clear with this concept.

Merci d’avance ! 

Bonne journée!